graphics: allow IAllocator 2.0 and IMapper to 2.1

Allows IAllocator 2.0 and IMapper 2.1 so that Cuttlefish can advertise
API level 30 for R before 4.0 is implemented.

Bug: b/136016160
Test: Compiles and boots
Change-Id: I6d8ebc7013a2887521358b1ba73a2def14c20b9a